As the power density (e.g., thermal design power) of contemporary processors (e.g., CPUs, GPUs, etc.) increases, thermal management becomes more and more challenging, especially when multiple high-density processors are packaged in one system (e.g., into a single server). Therefore, traditional air cooling solutions (e.g., using either heat sinks or heat pipes) generally are not able to satisfy thermal management requirements. Immersion cooling, e.g., in which IT equipment/components are immersed in an immersion cooling fluid, offers one solution. Generally, there are two types of hardware solutions for immersion cooling—vertical designs and horizontal designs. Vertical designs use similar design form factors as traditional air cooling IT racks, but the servers, e.g., a 1U, 2U or 4U, etc., typically are fully contained and filled with a fluid, that is, the fluid only is contained in each individual server. These designs can be generally expensive, however, and also can put high requirements on individual server sealing, can require significant amount of fluid, can be difficult to maintain and service, and may have high failure possibilities. Known horizontal hardware designs may provide several advantages over existing vertical designs, but current horizontal designs generally are not sufficiently energy efficient, and further may have inefficient fluid usage and bad fluid management. The present disclosure is directed to an immersion cooling thermal management systems and methods that address these and other related and unrelated issues in the art.